How to Increase the Value of Coconut Shell Charcoal to be Activated Carbon Part IV

Post On : 28/12/2017

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According to SII No.0258 -79, a good active charcoal has the following requirements as listed in the following table:

Active Carbon Specifications

Type

Requirements

The missing part on heating is 950 C.

Maximum 15%

Water

Maximum 10%

Ash

Maximum 2,5%

Non-heating part

Not Real

Absorption capacity of solution I

Minimum 20%

Activated carbon is divided into 2 types: active charcoal as charcoal and activated charcoal as absorber of vapor.

1. Activated charcoal as pale.

Usually in the form of a very fine powder with a pore diameter of 1000 A0 which is used in the liquid phase. Generally serves to remove substances that cause unexpected color and odor and solvent free from substances disturbing and other uses in the new chemical and industrial industries. This activated charcoal is obtained from sawdust, paper making waste or from raw materials that have small densities and have weak structures.

2. Activated charcoal as a vapor absorber.

Usually very granular or pellet-shaped with a pore diameter ranging from 10-200 A0. The pore type is finer and is used in the gas phase which serves to recover the solvent or catalyst on the separation and purification of the gas. Generally, this charcoal can be obtained from coconut shell, bone, brick or raw material that has a hard structure.

With respect to the raw materials used in the manufacture of activated charcoal for each type, the above statement is not a requirement.

With the process of activated carbon oxidation produced consists of two types, namely:

1. L-carbon (L-AC)

Activated carbon made by oxidation at a temperature of 300oC - 400oC (570o-750oF) using air or chemical oxidation. L-AC is particularly suitable for adsorbing dissolved ions from heavy metal bases such as Pb2 &plus;, Cu2 &plus;, Cd2 &plus;, Hg2 &plus;. The acidic surface character will interact with the base metal. Regeneration of L-AC can be performed using an acid or salt such as NaCl which is almost the same treatment in ion exchange.

2. H-carbon (H-AC)

The activated carbon produced from the cooking process at a temperature of 800 -1000 C (1470 -1830 F) is then cooled to the inertial atmosphere. H-AC has an alkaline surface which is not effective in adsorbing heavy alkali metals in aqueous solutions but is more efficient in adsorbing organic chemicals, hydrophobic particles, and chemically low solubility in water. However, H-AC can be modified by raising the acidity number. Neutral surface will result in ineffective in reducing and adsorbing organic chemistry so as to effectively adsorb heavy metal ions with chelate complexes of organic and synthetic organic substances by neutralizing them.

In the application of either activated carbon used as adsorption medium, ballast or filtration media with a particular injection point, the design criteria of activated carbon dot points should be considered:

1. The carbon contained in the bag is directly inserted into the storage tank and mixed with water to prepare into a solution containing 0.1 kg of powdered activated carbon per 1 liter of solution. Preferably, if an installation has 2 tank solutions, then the supply of activated carbon solution to be put can be placed in 2 tanks, if the solution in one tank is empty, then the solution is available in the other tank to be applied without waiting for the preparation of the activated carbon solution the new one.

2. A mechanical agitator shall be provided in a storage tank to keep the activated carbon solution "suspended" in the solution or keep the solution in order not to compress

3. The solution is usually pumped into a tank that holds a number of solutions and will be fed for more than the next several hours. The tank should be easy to clean and maintain. This tank must have an anti-rust coating such as epoxy or bitumastic paint to protect it from corrosion.

4. The powder carrier powdered activated carbon pipe shall be mounted downward to the site of affixing, with fittings to encourage carbon that may precipitate and clog in the pipe. Pipes shall be made of rust free and erosion-free materials such as rubber, plastics and steel. Pipe thrusters and blade blades in storage tanks and tanks must be made of steel to resist rust and erosion.

5. The most common problem in the operation of powdered activated carbon is the handling of chemicals. Since it is powder-shaped, dust is a major problem, especially if a dry mixing system is used.

6. If powdered activated carbon is used continuously or if large quantities are used for a certain time, the transfer to the wet system should be considered

7. At the water treatment plant, the activated carbon flowing through the filter and entering the distribution system can produce "black water". Black water is usually caused by improper coagulation or high doses of activated carbon added just prior to filtration. To solve the problem, the point of affixing should be moved to a raw water tapper system or into a quick stirring bath

The activated charcoal is a porous solid, comprising mostly of free carbon elements and each covalently bonding. Thus, the surface of activated charcoal is non polar. In addition to composition and polarity, the pore structure is also an important factor. The pore structure corresponds to the surface area, the smaller the pores of the activated charcoal, resulting in greater surface area. Thus the adsorption rate increases. To increase adsorption speed, it is recommended to use activated charcoal that has been mashed. The most important nature of the active charcoal is its absorption. In this case, there are several factors that influence adsorption absorption, namely:

1. Properties of Absorption

Many compounds can be adsorbed by activated charcoal, but their ability to adsorb is different for each compound. The adsorption will increase according to the increase in the size of the absorption molecule of the same structure, as in the homologous series. Adsorbtion is also influenced by functional groups, functional group positions, double bonds, chain structures of absorption compounds.

2. Temperature

In the use of activated charcoal it is advisable to observe the temperature at the time of the process. Factors affecting the temperature of the adsorption process are the viscosity and thermal stability of the absorption compound. If the heating does not affect the properties of the absorption compound, such as color change or decomposition, the treatment is carried out at its boiling point. For volatile compounds, adsorption is carried out at room temperature or whenever possible at lower temperatures.

3. pH (Degree of acidity).

For organic acids, adsorption will increase when the pH is lowered, ie by the addition of mineral acids. This is due to the ability of mineral acids to reduce the ionization of organic acids. Conversely, if the pH of organic acid is increased by adding alkali, adsorption will decrease as a result of salt formation.

4. Spell Time

When activated charcoal is added in a liquid, it takes time to reach equilibrium. The time required is inversely proportional to the amount of charcoal used. The difference is determined by the dose of activated charcoal, stirring also affects the tangency. Stirring is intended to allow the activated charcoal particles to be in contact with the sorption compound. For a solution that has high viscosity, it takes longer tangent time.

Activated carbon is a multifunctional material that has almost been used by many industries. Applications on the use of activated carbon can be seen from the table below:

Table.2 Applications of activated carbon use in industry.

No.

User

Usability

Mesh

1.

Drug and food industries

Filtering, deodorizing and taste

8×30, 325

2.

Liquor and light

Color removal, smell on drinks

4×8, 4×12

3.

Petroleum Chemistry

Refining raw materials

4×8, 4×12, 8×30

4.

Water Purifier

Color removal, odor of resin removal

5.

Shrimp farming

Purification, removal of ammonia, nitrite, penol, and heavy metals

4×8, 4×12

6.

Sugar Factory

Removal of dyestuffs, absorbing the filtration process becomes more perfect